code: def test_node_no_inputs(datadir):
      model = onnx.load(datadir.file("keras_linear_131.onnx"))
      while len(model.graph.node[0].input) > 0:
          model.graph.node[0].input.pop()
      parser = NetworkParser()
      with pytest.raises(ValueError) as excinfo:
          parser.parse_network(model.graph, None, None)
      expected_msg = """Nodes must have inputs or have op_type \"Constant\". Node \"StatefulPartitionedCall/keras_linear_131/dense/MatMul\" has no inputs and op_type \"MatMul\"."""
      assert str(excinfo.value) == expected_msg
  
file_path: OMLT/tests/io/test_onnx_parser.py
imports: import pytest
  from omlt.dependencies import onnx, onnx_available
label_desc: Use image node_id 10 for calling a global function with example usage: test_node_no_inputs(datadir) without return types